Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J38/00—Regeneration or reactivation of catalysts, in general
  • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J38/00—Regeneration or reactivation of catalysts, in general
  • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
  • B01J38/12—Treating with free oxygen-containing gas
  • B01J38/18—Treating with free oxygen-containing gas with subsequent reactive gas treating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/90—Regeneration or reactivation
  • B01J23/92—Regeneration or reactivation of catalysts comprising metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
  • B01J27/28—Regeneration or reactivation
  • B01J27/32—Regeneration or reactivation of catalysts comprising compounds of halogens
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J38/00—Regeneration or reactivation of catalysts, in general
  • B01J38/02—Heat treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J38/00—Regeneration or reactivation of catalysts, in general
  • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
  • B01J38/12—Treating with free oxygen-containing gas
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/584—Recycling of catalysts

Definitions

• the present invention relates to a process for the regeneration of fluorination catalyst based on Cr(III) compounds optionally supported.
• fluorination catalysts of industrial interest are known, based on Cr(III) oxides/oxyfluorides optionally supported on alumina, fluorinated alumina, aluminium trifluoride, in the reactions in gaseous phase, at high temperatures, between HF and halogen-containing hydrocarbons in order to introduce fluorine atoms.
• Such catalysts during their use in an industrial fluorination plant are subjected to deactivation due to the deposit on their surface of organic contaminants comprising carbonaceous residues and/or organic oligomers deriving from cracking and/or oligomerization of the organic compounds put to react.
• oxidizing gas such as air or oxygen/nitrogen mixtures at sufficiently high temperatures (300°-500°C.) to cause the combustion of the organic contaminants.
• the process according to the invention comprises
• phase b) of gaseous aliphatic hydrocarbons one could expect that their contact with a so active catalytic surface as that of the catalysts based on Cr(III), in particular of Cr 2 O 3 and/or Cr(III) oxyfluoride, and the high temperatures employed led to various reactions of cracking or oligomerization of the hydrocarbon molecule, with formation of carbonaceous and/or pitch compounds, which by soiling the surface of the catalyst lower the activity thereof.
• the Applicant has instead unexpectedly found that by the use in phase b) of aliphatic hyudrocarbons, mixed in particular ratios with an inert gas and of particular temperatures, no carbonaceous deposits form on the surface of the catalyst but instead the reduction of Cr(VI) compounds to active Cr(III) compounds is obtained.
• An object of the present invention is therefore a process for the regeneration of a fluorination catalyst based on Cr(III) compounds optionally supported, exhausted for the presence on its surface of organic contaminants, which comprises:
• the inert gas employed in phases a) and b) is preferably nitrogen.
• the aliphatic hydrocarbons employed in phase b) preferably contain from 1 to 4 carbon atoms such as methane, ethane, propane and butane, butane or propane and their mixtures are preferred and their amount in admixture with the inert gas preferably ranges from 1 to 3% by volume.
• the treatment temperature in phase b) preferably ranges from 310°to 340° C., while the pressure is not critical, as it can range from the atmospheric one to about 5 relative bar.
• the time of the treatment in phase b) is generally lower than 1 hour.
• the process according to the invention is particularly suitable for the regeneration of a fluorination catalyst based on oxide and/or oxyfluoride of Cr(III) supported on AlF 3 , Al 2 O 3 or fluorinated Al 2 O 3 , which has been utilized in the fluorination in gaseous phase with HF of halogen-containing hydrocarbons.
• a catalyst based on oxide and/or oxyfluoride of Cr(III) supported on AlF 3 can be continuously utilized for long periods of time in an industrial plant for preparing HCFC-123 from perchloroethylene and HF as described in U.S. Pat. No. 5,262,574, by alternating production periods with regenerations cycles according to the process of the invention, without undergoing substantial losses of chrome and of catalytic activity.
• TPO and TPR analyses were carried out by letting flow, respectively an oxidizing gas and a reducing gas, on a catalyst sample while it is heated progressively from the room tempeature to 700° C. at a programmed rate of 10° C./min and determining the variation of the composition of the analysis gas in comparison with a reference gas flow which does not pass on the sample.
• the Cr(VI) compounds were extracted from a catalyst sample by washing with acidified water and, successively, titrated with KI/thiosulphate.
• the catalytic test comprises the use of a catalyst sample in the standard fluorination of HCFC-133a (CF 3 CH 2 Cl) with anhydrous HF in a molar ratio 133a/HF of 1:4, at a temperature of 320° C.
• the catalyst after having continuosuly run until its catalytic activity, evaluated by catalytic test, has fallen to 70% of its initial value, is regenerated in situ by the following treatments in sequence:
• the TPO analysis does not show the presence of detectable amounts of organic contaminants and the catalytic test shows that the catalyst has the same activity as the initial fresh catalyst.
• the so regenerated catalyst is then brought again into operation in the synthesis of HCFC-123 where it acts in the same way as the initial fresh catalyst.
• Example 1 was repeated except that phase b) was carried out with a gaseous nitrogen/propane mixture containing 10% by volume of propane and for 25 minutes.
• phase b) was carried out with a gaseous nitrogen/propane mixture containing 10% by volume of propane and for 25 minutes.
• the catalyst does not show the presence of Cr(VI), but at the TPO analysis it shows the presence of 0.3% by weight (expressed as carbon) of organic contaminants.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Catalysts (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Exhaust Gas Treatment By Means Of Catalyst (AREA)

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Publications (1)

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Citations (2)

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• 1996
  • 1996-05-06 IT IT96MI000891A patent/IT1282960B1/it active IP Right Grant
• 1997
  • 1997-04-24 DE DE69717191T patent/DE69717191T2/de not_active Expired - Fee Related
  • 1997-04-24 EP EP97106795A patent/EP0806241B1/en not_active Expired - Lifetime
  • 1997-04-24 AT AT97106795T patent/ATE228032T1/de not_active IP Right Cessation
  • 1997-05-02 US US08/850,771 patent/US5817895A/en not_active Expired - Fee Related
  • 1997-05-02 IN IN789CA1997 patent/IN191115B/en unknown
  • 1997-05-02 JP JP9114865A patent/JPH1043607A/ja active Pending
  • 1997-05-05 AU AU20034/97A patent/AU712733B2/en not_active Ceased
  • 1997-05-05 TW TW086105944A patent/TW409073B/zh not_active IP Right Cessation
  • 1997-05-05 BR BR9703059A patent/BR9703059A/pt not_active IP Right Cessation
  • 1997-05-06 CN CN97111148A patent/CN1091652C/zh not_active Expired - Fee Related
  • 1997-05-06 KR KR1019970017241A patent/KR970073686A/ko not_active Ceased
  • 1997-05-06 CA CA002204584A patent/CA2204584A1/en not_active Abandoned

Patent Citations (2)

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